The activities of the StB (Státní tajná bezpečnost, the State Secret Police) included space eavesdropping via operational technical devices (“bugs”). The StB used the bugging from the very start of their activity in 1948. In 1977, when the Charter 77 was drawn up, the StB developed a modern-control transmitter TI-699 and used it for a remote control of the “bugs” installed in dissidents’ flats, but also e.g. in foreign nationals’ hotel rooms or diplomats’ flats.
The declaration of the “Charter 77” movement, whose initiators included Jan Patočka, Václav Havel, Zdeněk Mlynář, Jiří Němec, and a number of others who criticized the state authorities for the failure to adhere to civil and human rights, Czechoslovakia had committed to by signing the Helsinki treaties. The movement became one of the major manifestations of resistance against the Communist regime.